Novel marker to predict rupture risk in tubal ectopic pregnancies: the systemic immune-inflammation index

Ectopic pregnancy is a life-threatening condition; delaying treatment can result in mortality or serious complications. Identification of a biomarker that can predict tubal rupture may be helpful for guiding treatment. In this study, we evaluated the association between serum β-hCG, biochemical markers, Systemic Immunity-inflammation Index (SII) score, and the trophoblastic invasion stage.

Tubal pregnancy was classified into three groups based on the depth of trophoblastic infiltration: stage I - limited to the mucosa; stage II - invaded the muscular layer, and stage III - invaded the serosa/subserosa of the tuba uterine. The association between groups, serum β-hCG, biochemical markers, and the SII score were assessed.

There was no significant difference between the groups, hemoglobin, platelet count, MPV, RDW, NLR or PLR values (p > 0.05). A ROC analysis was performed to evaluate the accuracy of serum β-hCG predictions for infiltration level. At a 95% confidence interval upper limit, cut-off value of the serum β-hCG that best predicted stage III trophoblastic infiltration, was 2799 mIU/mL, with 78.9% sensitivity, 53.8% specificity (positive predictive value was 71.4%, and a negative predictive value was 63.6%). Moreover, ROC curve analysis showed that The SII value of 792 was the best predictor of trophoblastic infiltration at stage III, with a sensitivity of 92.3% and a specificity of 63.1%.

A linear relationship exists between depth of trophoblastic infiltration and serum β-hCG and the SII were observed. These findings suggested that the SII score can be used for predicting tubal ectopic pregnancy rupture.